What started out as a developer cloud during the Summer of 2012, the OpenStack based private cloud at eBay has since grown into a multi-tenant multi-region self-service cloud. The work loads we now support range from development use cases, to CI farms, as well as external facing business critical applications. We act and think like a public cloud and follow certain princples and practices on how we design, build, and operate . These pracrices enable us to maintain developer agility, operational efficiency and elasticity. In this session, we would like to share our adoption story from the time it began till now, and present our design principles, architecture, practices, and challenges in operating multi-tenant private clouds using OpenStack at the core.